Coil changing device



n- 9 5- E. R. PFAFF ET AL 1,936,525

COIL CHANGING DEVICE Filed Oct. 26, 1952 2 Sheets-Sheet 1 72 a /FFO/PZ7 z. coo/l,

S50E55 POETHEZ, JP.

6 7 Br m 67 abfowvu; S

' eacte -j am a. rim. Clifford I... Boethel, In. Chicago. 1..

Application mm as, iosasei-ui No. mass uaignonto L E.

18 claims. (Cl. 171- 119 x In tuning radio receivers to various resonances in the short wave spectrum and broadcast spectrum it has beenfound desirable to use inductances of different values to cover the various parts of the spectrum. The broadcast spectrum,

extending from 550 to 1500 kilocycles may be readily covered by a single set of inductance coils; but to enable the receiver to be tuned to the spectrum for the short waves below 200 meters or above 1500 kilocycles it is advisable to selectively couple into the circuit coils ofsubstantially smaller inductances as the shorter wave lengths are to be received. It has also been found that sensitivity and selectivity of the receiver and the i5 facility with which the circuit may be tuned to resonance is better obtained by including several sets of inductances which may be selectively coupled into the circuit. In the past the changing of inductances has been accomplished by the use of plug-in coils; that is the desired inductances were wound upon a form or otherwise held in their desired conformation and were inserted in a socket for coupling the same into the circuit in much the same manner as a radio tube is placed in a socket. This was done manually, that is the desired coil was selected and inserted in the socket; and when the operator desired to receive signals on a different part of the spectrum. he

removed that coil andinserted another of the proper characteristics to permit the receiver to be tuned to the desired part of the spectrum.

This made it necessary for the receiver to be.

accessible for the insertion of the separate coils. Easy insertion of the coils is sometimes diflicult because of the inability to align the contacts with the proper receiving apertures in the sockets.-

The manual operation also takes time.

It is therefore within the purview of this invention to provide a means for eliminating the manual changing of plug in coils.

Another object of the invention is to provide a compact coil arrangement which permits the coils to be shifted into and out of the circuit with ease and speed. Still other objects of the invention will become apparent from the following description of an embodiment thereof which together with the accompanying drawings forms a part of this specification.

Referring to the drawings, throughout whichlike parts are designated by like reference characters;

Figure 1 is a bottom plan view of the spider and coil-assembly; v Figure 2 is an elevational view with certain parts broken away and shown in section;

. frame,

Figure: is a bottom plan view of the stationary contacts used in conjunction with the coil assembly and their supporting means;

Figure 4'is a section taken on the line H of Figure 3;

Figure 5 is. a fragmentary sectional view of the spider or coil supporting member;

Figure 6 is a view taken on the line 6-6 of Figure 5; i

Figure 7 is a fragmentary elevational view showing the spider assembly and the stationary contact arm; one of .the 0011- supports being removed for clarity in exposition;

Figure 8 is a perspective view of a control switch. p

The device comprises generally a rotary member which supports the various induction coils and a stationary member which supports a plurality of resilient contacts into contact with which the rotary member is adaped to be rotated by means of the driving mechanism for connecting the desired inductance into the circuit. I

More specifically it includes a rectangular 1,-adapted to be secured to the bed plate 2, or otherwise, within a receiver chassis by suitable bolts 3. The frame 1 is provided with an enlarged base 4 which affords a larger bearing surface for attaching the same within areceiver chassis. Parallel with the base 4 is an end-member 5 supported by side members 6 and 'I.

The lower surface of the base 4 is provided with a downwardly extending-portion 8 adapted to carry a cross beam 9 which acts as a stationary contact support, being secured to the frame at 8 by screws 10.

The laterally extending arms of the member 9 each support contact tables 11. The tables are preferably constructed of insulating material, being spaced from thearms by tubular spacers 12 and secured to the arms of the support 9 by screws 14 which extend through the spacers 12 and are threaded into the support 9. This arrangement is best shown in Figures 3, 4, and 7. The base of the table 11 is provided with a longitudinal slot 20, Figure 4, extending intermediate the sleeves 12. A strip of non-conductive material 21 is secured to the underside of the table 11 below and covering the slot 20. Slots 22 are provided in the strip 21 and extend from one edge into the body of the strip. A pair of parallel strips 24 and 25 of non-conductive material are provided adjacent the slot 20 on the upper surface of the table and overhang the slot on each side. A plurality of holes 27 are provided in the table 11 in two rows spaced from the edge and parallel to the slot. Contact members 30, as best shown in Figure 4, are provided and are supported by the table.

Each contact member comprises a body having an elongated contact surface 31 with a plurality of transverse grooves 32 extending across the surface. The surface of the contact member adjacent to the contact surface is provided with a pair of slanting faces 33. Adjacent the extremities of the contacts are a pair of upwardly extending posts 34 adapted to extend throughthe holes 27 in the table 11. About the posts between the body 30 and the underside of the table 11 are disposed helical springs 35- which bear against the body of the contact and against the under surface of the table 11 urging the contact away from the table. A retaining arm 38 at the central portion of the contact extends upward through the slots 22 of the member 21 and is provided with a T-shaped end 39 adapted to rest on the strips 24 and 25 maintaining the contact in position on the table. Arms 40 are provided on the ends of the contacts and are for pigtail connections with the rest of the receiver not shown.

As best shown in Figure 3, each of the contact assemblies is substantially the same being provided with six of the individual resiliently supported contacts 30 for each arm and extend diametrically opposite to each other.

The movable coil assembly is adapted to be supported under and adjacent to the stationary contact assembly. It, together with its rotating mechanism, includes a supporting shaft rotatably journalled in bearings 51 and 52 in the portions 5 and 4 respectively of the frame 1. The mid-portion of the shaft is provided with a gear 53 enmeshed with a pinion gear 54. The pinion gear is secured to a shaft 55 rotatably journalled in a bearing 56 in the leg 6 of the frame 1.

The shaft is adapted to extend beyond the confines of the receiver chassis and is provided at the end with a control lever 49, Figure 1, and provides manual means for rotating the shaft 50. The

shaft 50 extends through the end 4 of the frame' 1, and is provided with a cam 59 for operating a switch 60 hereinafter referred to in detail.

The other end of the shaft extends down through the end'5 of the frame and a spider 5'? is secured to the end. The spider comprises a fiat center portion 61 and has a plurality of radially extending arms. Positive driving connection between the spider and the shaft is provided and may consist in a boss 51 of rectangular cross section on the shaft 50 engaged in an aperture of like conformation in the spider. A flange 58 is provided integrally with the shaft 50 for absorbing the thrust, a bearing washer 59 being interposed between the flange 58 and the frame portionl5. The radial arms each comprises a cylindri'cal' portion- 65 with a flange 66 and support thereon tubular forms 67 upon which inductance coils'68 may be wound.

A contact board is provided for each inductance coil and includes an insulated base 70 secured to the forms 67 and extending longitudinally of the forms and spaced therefrom by sleeves 72. Bolts '73 extend through the forms and sleeves and secure the base '70 to the forms 67 and the forms 6'7 to the arms 65. Fixed contacts are secured to the base in alignment with the resilient contacts 30 on the stationary table 11. Leads '76 extend from the coils to contacts '75. These leads only being shown in Figure 7, but it is to be understood that similar leahdss are to be run to their contacts for all the co Means is provided for indexing the relative position of the coils to the stationary contacts and comprise an index plate BOembedded in the upper surface of the spider body 60, as best shown in Figures 5 and 6. The index plate is provided with a plurality of index detents 81 at spaced intervals adjacent the periphery. A pair of indexing plungers 82 are supported in sockets 83 in the frame 5 and are adapted to ride upon the surface of the plate 80. The index plungers include a plunger element 82 slidably journalled in the socket 83 formed in the member 5. The plungers are hollow and a spring 84 extends into the plunger and against the end wall of the socket and forces the plunger downward against the surface of the plate 80.

During rotation of the spider the plungers 82 rest on the surface of the plate and are adapted to drop into the detents 81 impeding the movement of the spider. The detents are so arranged that the two plungers engage two detents simultaneously and are so positioned that when they are engaged in the detents the fixed contacts carried by the movable coils are in the center of the resilient stationary contacts carried by the table 11. When the inductances are again changed the lever 49 must be rotated with suflicient force to overcome the restraining action of the index plungers 82. When the plungers are out of contact with the detents 81 the spider rotates relatively easy until the index plungers again drop into the detents when the next succeeding coil in rotation is in alignment with the contacts.

The shaft 50 which extends upward through the bed plate carries at the end a cam 59 which is adapted to contact with a movable arm of a switch 91 secured to the chassis by a bracket 92. The switch is adapted to change the receiver circuit and consists of the contact arms 90, 93 and 94, '90 being the movable arm and disposed between the two fixed arms, and when in contact with either of the adjacent contacts is adapted to change the characteristics of the radio circuit as different coils on the receiver are shifted into the circuit.

The induotances on the spider arm are adapted to cover the entire broadcast band and short wave spectrum. When it is desired to tune the receiver to a particular station, if it should be a broadcast station, the lever 49 would be rotated to bring the broadcast inductance into the circuit. This rotation will be communicated through the shaft 55 to the gears 54 and 53 thence rotating the shaft 50. Rotation of the shaft 50 rotates the spider and supported inductance coils. The coil contacts '75 on the coils when approaching the fixed contacts 30 are adapted to engage the slanting surface 33 which permits the contacts 75 to push the fixed resilient contacts upward against the pressure of the springs 35 allowing the contacts to slide onto the center portions 31 of the contacts, all of the inductance contacts '75 being aligned with the resilient fixed contacts on the stationary arms 9. The grooves 32 on the resilient contacts assist in keepingthe faces '75 of the contact clean, exercising a scraping action thereon. When the coil contacts reach the center of the fixed contacts the index pins 82 drop into the indexing detents 81 in the index plaltse 80 and resist the furthermovement of the coi In the device as shown -in the drawings the inductances 88 on the arms 67, Figure 1, which may be adapted for receiving the usual broadcast station known commonly as long wave stations, is shownas being in contact with the llxed contact. It will be noted'that the coil form opposite to the broadcast inductance has no winding upon it. Actually some of the contacts for the opposite broadcast form have been short cir-' cuited by a lead 48 which effects a change in the characteristics of the receiver circuit essential to tuning the circuit.

The rotary spider having been rotated until I the broadcast coil is in contact, thus shifting the broadcast inductances into the circuit, the set may now be tuned for the entire broadcast range. When it is desired to change to short waves or to stations above the broadcast range inkilocycles, .the lever 49 is rotated to shift the desired inductances such as are on the arms 67 or 67" into the circuit. Three sets of inducta'nces are shown as being provided to cover the entire short wave spectrum. However, it is to be understood that, although only eight arms are shown and with only seven inductance coils thereon, it is entirely within the province of this invention to provide more or less arms and inductances as seen flt, and that the ranges below the 550 kilocycle range may also be covered by additional inductances.

The flat conformation of the device permits the same to be readfly installed in relatively small space within the receiver. It also permits the sets of coils as used to operate in their greatest efficiency because of their electrically inductive alignment, however, it is not essential that the coils be positioned exactly as shown, as the inductive alignment may not be necesary in some instances, and we do not desire tolimit our application to the precise positioning shown.

91 are coupling condensers used to more efii-. ciently couple the inductances upon the arms together and in the circuit.

Having thus described the invention, we are aware that numerous and extensive departures maybe made therefrom but without departing from the scope of the appended claims.

' the coils, all the contacts on all the spiders being disposed in a common plane, means to include the coils in an electrical circuit comprising a contact carrying member disposed in a plane adjacent to the coil contact plane, contacts resiliently supported thereon, contacts for said members having extended contact faces and provided with cam surfaces at each end of the face, said resilient contacts adapted to be selectively contacted with the coil contacts.

2. In an inductance changer for a radio receiver, a spider, a plurality of radially disposed arms on the spider, means to rotate the spider, a plurality of inductance coils wound on the arms, contact carrying members secured to each arm and contacts on the members electrically connected to the coils all of the said contacts on all the spiders being in a common plane, means to include the coils in a circuit comprising a contact carrying member disposed in a plane adjacent to the coil contacts, resiliently supported contacts thereon, said contacts having extended 3 contact faces andprovided with cams on each end extending in the direction of travel of the coil contacts for selective contact with the said coil contacts.

3. In an.inductance changing device for an electrical circuit comprising, a rotatable spider, arms radially extending from the spider, a flat portion at the center of the spider, an index plate embedded in said portion, indexing means comprising a spring-pressed stop adapted to cooperate with said plate to stop the spider in a predetermined position, inductance coils on the spider, contacts for said coils, a contact carrying member, resilient contacts supported thereon and adapted to cooperate with the coil contacts to electrically couple a selected coil into a circuit when'the spider rotation is stopped by the index means.

7 4. In an inductance changing device for. an electrical circuit, a spider, a plurality-of arms extending radially therefrom, inductances carried by the arms, contacts for the inductances and strips to carry the contacts, said contacts upon said strips being disposed in a common plane,- a support for the spider comprising a frame adapted for securing to a receiverchassis, a rotatable shaft carried by the frame and journalled for rotation thereon, driving means for the shaft, said spider being carried by shaft and being rotatable thereby, means to couple said inductances into an electrical circuit comprising stationary contacts for electrical connection into the circuit,

means to support the contacts comprising a pair of armscarried by the frame and extending outwardly therefrom juxtaposed to the spider, said contacts being resiliently disposed on said arms and extending in a plane contiguous to the plane of the contacts for the inductances, said inductances upon rotation adapted to be selectively engaged with their contacts in contact with the stationary contacts.

5. In an inductance changing device for a radio receiver comprising a stationary frame adapted to be secured to a receiver chassis, a driven shaft rotatably journalled in said receiver, means to rotate the shaft comprising a ring gear disposed on the shaft, a pinion gear in mesh with the ring gear, a drive shaft for the pinion gear adapted to extend beyond the confines of the chassis, a lever upon the drive shaft for manual rotation thereof,

an inductance carrying member supported by said driven shaft comprising a spider, a plurality of radially extending arms upon the spider, inductances of various inductance disposed on said arms, means to electrically couple said inductances into the circuit comprising a stationary contact member supported by the frame, contacts resiliently disposed on said member and adapted for connection into an electrical circuit, contacts supported by the spider arms and connected to the inductances, said contacts being disposed in a plane adjacent to the stationary contact member, said inductances adapted to be selectively contact arms carried by the frame and resilient contacts carried by the said spider adapted to be rotated to shift the movable coils into contact with the stationary inductances to selectively couple any desired inductance into the circuit, said switch being adapted to change the type of coupling in the circuit when certain of the coils are in the circuit. s

7. In an inductance and circuit changin device for a' radio receiving circuit, a stationary frame upon the receiver chassis, a driven shaft journalled in the frame, a switch, a cam on the driven shaft for operating the switch and arranged to control a circuit, a spider rotated by the shaft, a plurality of radially disposed inductances carfied by the spider, contacts for the inductances, stationary resilient contacts carried by the frame, said inductances adapted to be ro-. tated to contact the inductance contacts of a desired inductance with the resilient contact, said cam adapted to operate said switch to change the circuit when certain selected coils are coupled into the circuit.

8. In a coil changer for radio receivers, a stationary frame adapted to be secured to the receiver chassis, a driven shaft rotatably journalled in said frame, a drive shaft rotatably journalled in the frame and adapted to extend beyond the confines of the chassis, a control lever carried by the drive shaft for rotating the same, intermeshing gears on the drive and driven shaft for communicating rotary motion to the driven shaft, a spider carried by the driven shaft, radially extending arms upon the spider, inductance coils carried by the arms, contacts for the coils carried by the arms with the contact faces of all the con-' tacts disposed in a common plane, means for selectively coupling the coils into the circuit comprising a stationary arm extending from said frame, a contact carrying member carried by the arm, contacts resilientlysupported on said contact carrying member; said contacts having extended contact surfaces provided with elongated portions at the ends and adapted to be electrically coupled into a receiver circuit, a switch for changing the coupling of a receiver circuit, a cam rotatable by the driven shaft to actuate the switch, said spider adapted to be rotated to selectively shift the coil contacts into engagement with the resilient stationary contacts, said switch adapted to change the circuit when certain of the inductances are shifted into the circuit.

9. In a coil changer for radio receivers, a stationary frame adapted to be secured to the receiver chassis, a driven shaft rotatably journalled in said frame, a drive shaft rotatably journalled in the frame and adapted to extend beyond the confines of the chassis, a control lever carried by the drive shaft for rotating the same; intermeshing gears on the drive and driven shaft for communicating rotary motion to the driven shaft, a spider carried by the driven shaft, radially extending arms upon the spider, inductance coils carried by the arms, contacts for the coils carried by the arms with the contact faces of all the contacts disposed in a common plane, means for selectively coupling the coils into the circuit comprising a stationary arm extending from said frame, a contact carrying member carried by the arm, contacts resilientlysupported on said contact carrying member, sazd contacts having extended contact surfaces provided with elongated portions at the ends and adapted to be electrically coupled into a receiver circuit, a switch for changing the coupling of a receiver circuit, a cam Landsat rotatable by the driven shaft to actuate the switch, said spider adapted to be rotated to selecively shift the coil contacts into engagement with the resilient stationary contacts, said switch adaped to change the circuit when certain of the inductances are shifted into the circuit, and means to selectively position the-inductances in positive contact with the stationary contacts comprising a plate carried by the spider, index holes in the plate, and a spring-pressed stop for engagingthe holes in the plate to retard the movement of the spider.

10. An inductance changing circuit, a stationary frame adapted to be secured to the receiver chassis,-a spider secured -to and rotatable upon said frame, a plurality of inductances carried by the spider, a fixed contact supdevice for a. radio porting member disposed adjacent the plane of] circuit, a stationary frame adapted to be secured to the receiver chassis, a spider secured to and rotatable upon said frame, a plurality of radially extending inductances carried. by the spider, a fixed contact supporting memberdisposed adjacent the plane of rotation of the inductances, contacts carried by the inductances, resilient contacts carried by the fixed contact carrying member and including elongated contact faces, extending in the direction of rotation of the inductance, contacts and having transverse grooves extending across their faces adapted to assist in maintaining a clean connection between the contacts,

12: An inductance changing device for a radio circuit, a stationary frame adapted to be secured to the receiver chassis, a spider secured to and rotatable upon said frame, a plurality of radially extending inductances carried by the spider, a fixed contact supporting member disposed adjacent the plane of the rotation of the inductances, contacts carried by the inductances, resilient contacts carried by the fixed contact carrying member and including elongated contact faces in the direction of rotation of the inductance contacts their faces adapted to assist in maintaining a clean connection between the contacts, the ends of the contacts being provided with cam surfaces adapted to engage the inductance contacts.

13. In an inductance changing device for radio receivers, a frame secured to the receiverchassis, a plurality of fixed contacts carried by the frame, a rotatable member and a plurality of radially disposed inductances carried thereby, and rotatable as a unit, contacts for said inductances extending therefrom in a common plane and adapted to be selectively coupled with the fixed contacts, some of the inductances being arranged in pairs and disposed oppositely to each other and in inductive relation between each such pair, said fixed contacts being disposed in a plane adapted to permit the inductances to be rotated into contact therewith and including resiliently suspended elongated contact members extending in the direction of rotation of the inductances and provided with cam surfaces at their ends adapted to engage and permit the resilient contacts to ride against the coil contacts from either direction and transverse grooves disposed across said resilient contacts adapted to assist in maintaining a clean electrical contact between the fixed contacts and the inductance contacts.

14. In an inductance changing device for radio receivers, a frame secured to the receiver chassis, a plurality of fixed contacts carried by the frame and adapted to be connected with a receiver circuit, a rotatable 'member and a plurality of radially disposed inductances carried thereby and rotatable as a unit, contacts for said inductances extending therefrom in a common plane and adapted to be selectively engaged with the fixed contacts, inductances which engage with the contacts being arranged in pairs and disposed oppositely to each other and in inductive relation between each coil of each such pair,

15. In an inductance changer for a radio receiver, a spider, a plurality of radially disposed arms on the spider, means to rotate the spider, a plurality of inductance coils wound on the arms, contact carrying members secured to each arm and contacts on the members connected to the coils, all the contacts on all the spiders being disposed in a common plane, means to include the coils in an electrical circuit comprising a contact carrying member disposed in a plane adjacent to the coil contact plane, contacts resiliently supported thereon, contacts for said members having contact faces and provided with cam surfaces at each end of the face, said resilient contacts adapted to be selectively contacted with the coil contacts.

16. In an inductance or coil changer for radio receivers or the like, a rotatable inductance supporting member, a plurality of inductances carried thereby, contacts for said inductances, the contacts for each inductance extending in a line radially from the axis of the rotatable member, a fixed contact supporting member juxtaposed to the rotatable member, contacts carried thereby and comprising elongated contacts extending in a plane parallel to the plane of rotation of the rotatable member, said contacts being resiliently supported to permit tilting thereof in a longitudinal direction and adapted to be connected into a radio circuit.

17. In an inductance or coil changer for radio receivers or the like, a rotatable inductance supporting member, a plurality of inductances carried thereby, contacts for said inductances, the contacts for each inductance extending in a line radially from the axis of the rotatable member, a fixed contact supporting member juxtaposed to the rotatable member, contacts carried thereby and comprising elongated contacts extending in a plane parallel to the plane of rotation of the rotatable member, said contacts being resiliently "supported on springs disposed adjacent the ends to permit tilting thereof in a longitudinal direction and adapted to be connected into a radio circuit.

18. In an inductance or coil changer for radio receivers or the like, a rotatable inductance supporting member, a plurality of inductances carried thereby, contacts for said inductances, the contacts for each inductance extending in a line radially from the axis of the rotatable member, a flxed contact supporting member juxtaposed to the rotatable member, a row of contacts carried thereby and comprising elongated contacts extending in a plane parallel to the plane of rotation 01' the rotatable member, said contacts being resiliently supported to permit tilting thereof in a longitudinal direction and adapted to be connected into a radio circuit, said rotatable member adapted on rotation to engage the inductance contacts consecutively with the contacts of the row of fixed contacts from the axis toward the end of the row, the contacts of one or more inductances adapted to all be in contact with the fixed contactsupon attaining a certain predetermined flxed rotative position.

ERNEST R. PFAFF. CLIFFORD L. COON. GEORGE ROE'I'HEL, JR. 

